Methaqualone

2-Methyl-3-o-tolyl-4(3H)-quinazolinone

Quaalude, Sopor, Mandrax, Parest, Ludes

Psychoactive Class

Depressant Sedative Anxiolytic Muscle Relaxant GABAergic

Chemical Class

Methaqualone is a sedative-hypnotic depressant of the quinazolinone class.¹ Its sedative properties were first identified by researchers in the 1950s, and it was patented in the United States in 1962. During the 1970s, it saw widespread medical use for insomnia and muscle relaxation, as well as significant recreational popularity within the counterculture and disco scenes. Though largely discontinued as a pharmaceutical, it continues to be produced clandestinely, particularly in South Africa.² Illicit methaqualone products are often adulterated, sometimes with other CNS depressants.

Dosage & Duration

Dosage

Threshold~75 mg

Light75-150 mg

Moderate150-300 mg

Strong300-500 mg

Heavy500+ mg

Duration

Onset20-45 minutes

Peak2-4 hours

Offset1-2 hours

After Effects2-24 hours

Total4-8 hours

Half-life

4-60 hours

Subjective Effects

Effects vary widely by individual, dose, and context.

Forked from Subjective Effect Documentation

by Josie KinsSeptember 2015.

Reagent Testing

Loading reagent data

Expected colorimetric results are being prepared.

Pharmacology

Pharmacodynamics

Methaqualone acts primarily as a positive allosteric modulator of GABA-A receptors, enhancing the inhibitory chloride currents generated by GABA.³ Some minor direct agonist activity has also been observed, though it is not comparatively significant.³ Its binding site is located at the transmembrane β(+)/α(-) subunit interface, distinct from those of benzodiazepines, barbiturates, and neurosteroids, though it may partially overlap with the etomidate binding site.³⁴ Methaqualone may also function as a negative allosteric modulator at certain GABA-A receptor subtypes, and is therefore considered a mixed GABA-A receptor modulator.³ It shows negligible affinity for a wide array of other potential targets, including other receptors and neurotransmitter transporters.³

Pharmacokinetics

Methaqualone is readily absorbed from the gastrointestinal tract and distributes into body fat, liver, and brain tissue via plasma. Peak plasma concentrations are reached approximately 2 hours after oral administration.⁵ Its elimination half-life has been variably reported, with estimates ranging from approximately 4 hours to as long as 60 hours.

Metabolitesnone documented yet

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

DissociativesStimulants

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

1,2-BenzodiazepineAbametapirAcetazolamideAcetophenazineAgomelatine

TripSit

Tolerance

Full Tolerance

Tolerance to sedative-hypnotic effects develops quickly, often after only a few days of repeated dosing. Physical dependence can develop within about two weeks when moderate doses are used every day. Tolerance to euphoric effects appears to develop faster than tolerance to respiratory depression, substantially increasing overdose risk when users raise doses to regain earlier subjective effects.

Baseline Reset

1-2 weeks of abstinence in the absence of further consumption. Avoiding tolerance buildup generally requires spacing doses by several days up to about a week.

Half Tolerance

Approximately 3-7 days after cessation of use.

Cross Tolerance

GABAergic depressants, Barbiturates, Other sedative-hypnotics

Harm Potential

Addiction & Dependence

Psychological

High

Methaqualone is described as extremely addictive with high abuse potential.⁶ Psychological dependence is very common with regular use, particularly at doses over 600 mg per day. Users report severe cravings for the drug persisting for extended periods after cessation.

Physical

High

Physical dependence develops rapidly, with daily use of even moderate doses producing addiction within a couple of weeks.⁷ Withdrawal symptoms include restlessness, irritability, insomnia, tremors, nausea, vomiting, abdominal cramps, and muscle twitches.⁸ Severe withdrawal can involve mental confusion, delirium, hallucinations, high fever, and epileptic-like seizures that can be fatal.⁷⁸

Toxicity

Respiratory

Respiratory depression is a significant effect at higher doses and can progress to respiratory arrest in overdose; the combination with other depressants substantially increases this risk.⁹

Cardiovascular

Cardiac effects including reduced heart rate and blood pressure occur during use; cardiac arrest is possible in severe overdose.⁹

Renal

Kidney failure has been reported as a consequence of severe overdose.

Psychosis Risk

Paranoia, panic, and anxiety can occur during use, particularly at certain doses. More severe psychiatric effects including mental confusion, delirium, nightmares, and hallucinations are primarily associated with withdrawal rather than acute intoxication.⁸

Seizure Risk

Seizures represent a significant risk with methaqualone both in overdose and during withdrawal from chronic use.⁷⁸ Convulsions have been documented in both circumstances, with withdrawal seizures being potentially fatal. The drug has anticonvulsant properties at normal doses, but tolerance develops to this effect with repeated administration.¹⁰

History & Culture

Discovery and Development

Methaqualone was first synthesized in India in 1951 by M.I. Gujral as part of a research program seeking antimalarial compounds. Although the substance proved ineffective against malaria, researchers identified its hypnotic properties by 1955. A subsequent pharmacological study in 1957 confirmed…

Legality

By Country

United StatesSchedule I

Originally approved by the FDA in 1965 with minimal controls. Placed in Schedule II in 1973 following concerns about abuse potential. Moved to Schedule I in June 1984 after Congress passed legislation specifically targeting methaqualone.²¹ Under current law, it is illegal to manufacture, buy, possess, or distribute without a DEA license. Lemmon, the final domestic manufacturer, ceased production in November 1983.

AustriaIllegal (SMG)

Controlled under the Suchtmittelgesetz (Austrian Narcotics Act). Possession, production, and sale are prohibited without authorization.

GermanyAnlage II BtMG

Controlled under the Betäubungsmittelgesetz.¹⁹ Manufacturing, importing, possessing, selling, or transferring without license is prohibited. Initially sold over-the-counter in the 1960s before prescription requirements were introduced in 1963 following reports of misuse.

SwitzerlandControlled (Verzeichnis A)

Specifically listed as a controlled substance under Verzeichnis A of Swiss narcotics legislation. Unlike some jurisdictions, medicinal use remains permitted under appropriate licensing.

AustraliaSchedule 9

Classified as a prohibited substance with no recognized medical value. Possession, manufacture, and distribution require a license.

CanadaSchedule III CDSA

Controlled under the Controlled Drugs and Substances Act.¹⁸ Requires a valid prescription or license to legally possess. Pharmaceutical methaqualone remains available through legitimate prescription channels.

JapanControlled (Powerful Drug)

Designated as a 'powerful drug' in June 1964 after reports of widespread nonmedical use. Containers must display 'powerful' in red lettering. Sales restricted to pharmacies with mandatory record-keeping including recipient name, address, occupation, drug purpose, and transfer date. Prohibited for sale to individuals under 14 or those deemed unlikely to handle the substance responsibly.

United KingdomClass B

Initially controlled under the Drugs Prevention of Misuse Act 1970, making importation without Home Office license and unauthorized possession criminal offenses. The Misuse of Drugs Act 1971 was amended in July 1973 to include methaqualone, strengthening controls and increasing penalties.²⁰ Regulatory measures such as handwritten prescription requirements were implemented.

References

Source Pages

Citations

Automated synthesis
Information aggregated and synthesized using an autonomous workflow built by Josie Kins.

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